Object-oriented video system
First Claim
1. A coder for an object-oriented video system, the coder comprising(a) Input image means for receiving a sequence of input images, together defining a moving image, for coding;
- (b) An object separator arranged to separate out from the moving image a foreground object and a background object, the background object being relatively motionless with respect to the foreground object, the object separator utilizing(i) a potential background store, within which is built up, over a plurality of input images a potential background, and(ii) an accepted background store within which is stored at least some parts of the potential background which have persisted for a desired period; and
(c) A block coder arranged to code and classify blocks of the image and to produce an output date stream for storage or onward transmission, each coded block within the data stream being identified as relating either to the foreground or to the background object.
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Accused Products
Abstract
An object-oriented video system is implemented as a two layer object model in a software-only video compressor. Quadtree decomposition on an error metric between the input and transmitted images directs the coder towards a foreground layer of active image fragments. A rate buffering system limits the bandwidth by transmitting only the foreground blocks which most improve the image and are above some error threshold. A high fidelity background layer is identified and communicated to the decoder, which can be used to redraw background fragments as foreground objects move across them. Blocks can be coded by various methods, such as fractal transforms or truncated DCTs. The system can be implemented in RISC processors without the need for dedicated hardware. It is suitable for low bit rate applications with slowly varying backgrounds, such as personal video communications over packet networks, or closed circuit TV surveillance.
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Citations
26 Claims
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1. A coder for an object-oriented video system, the coder comprising
(a) Input image means for receiving a sequence of input images, together defining a moving image, for coding; -
(b) An object separator arranged to separate out from the moving image a foreground object and a background object, the background object being relatively motionless with respect to the foreground object, the object separator utilizing (i) a potential background store, within which is built up, over a plurality of input images a potential background, and (ii) an accepted background store within which is stored at least some parts of the potential background which have persisted for a desired period; and (c) A block coder arranged to code and classify blocks of the image and to produce an output date stream for storage or onward transmission, each coded block within the data stream being identified as relating either to the foreground or to the background object. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 25, 26)
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17. An object-oriented video system comprising:
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(1) A coder having; (a) Input image means for receiving a sequence of input images, together defining a moving image, for coding; (b) An object separator arranged to separate out from the moving image a foreground object and a background object, the background object being relatively motionless with respect to the foreground object, the object separator utilizing (i) a potential background object store, within which is built up, over a plurality of input images, a potential background, and (ii) an accepted background object store within which is stored at least some parts of the potential background which have persisted for a desired period; (c) A block coder arranged to code and sort blocks of the image and to produce an output data stream for storage or onward transmission, each coded block within the data stream being identified as relating either to the foreground or to the background object; and (2) A decoder adapted to receive the output data stream and to create a video signal therefrom. - View Dependent Claims (18, 19, 20, 21, 22)
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23. A method of operating a video system comprising:
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(a) receiving a sequence of input images, together defining a moving image; (b) separating out from the moving image a foreground object and a background object, the background object being relatively motionless with respect to the foreground object, including maintaining a potential background object store, within which is built up, over a plurality of input images, a potential background, and an accepted background object store within which is stored at least some parts of the potential background which have persisted for a desired period; and (c) coding and sorting blocks of the image and producing an output datastream for storage or onward transmission, each coded block within the datastream being identified as relating either to the foreground or to the background object. - View Dependent Claims (24)
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Specification